1. Field of the Invention
The present invention relates generally to the field of gamma ray spectroscopy monitoring and a system for accomplishing same to monitor one or more aspects of various isotope production processes. In one embodiment, the present invention relates to a monitoring system, and method of utilizing same, for monitoring one or more aspects of an isotope production process where the monitoring system comprises: (A) at least one sample cell located inside a hot cell that is connected to a medical isotope reactor, or other type of nuclear reactor; (B) at least one measuring port located in and through the hot cell and/or a hot cell wall, the measuring port forming at least one gamma ray window through the hot cell and/or a hot cell wall, where the measuring port has an inner gamma ray transparent plug located at the internal end thereof and an outer gamma ray transparent plug located at the external end thereof; (C) at least one adjustable collimator device operably coupled to the at least one measuring port; (D) at least one shutter located outside of the hot cell and operatively coupled to the outer end of the measuring port; and (E) at least one high resolution gamma ray spectrometer that is operably coupled to the hot cell and positioned in such a manner that gamma rays from the hot cell are supplied to the at least one high resolution gamma ray spectrometer through at least one opening in the shutter that is transparent to gamma rays.
2. Description of the Related Art
Many radio-isotopes are prepared by irradiation of a uranium-235 (235U) target or solution in a nuclear reactor and subsequent separation of the fission product isotopes of interest including, but not limited to, one or more of 99Mo, 137Ce, 131I, 89Sr, 133Xe 90Y, 99mTc, and/or 99Tc by chemical means. These purifications are usually carried out in a shielded “hot cell” on solutions of the fission or irradiation products. This is true whether the solutions are the result of irradiation of solid 235U targets or the product of an aqueous homogeneous reactor (AHR) or other radioactive solutions. As is known to those of skill in the art, the purity of the final product of various medical radio-isotopes is subject to various regulatory requirements set forth by, for example, The U.S. Food and Drug Administration.
Given the regulations and requirements placed on various medical radio-isotopes, it is necessary to evaluate the purification process and product purity. Many of the intended products, like 99Mo, 137Ce, 131I, 89Sr, 133Xe 90Y, 99mTc, and/or 99Tc and potential contaminants are gamma-emitting radioisotopes that can be measured by gamma-ray spectroscopy.
Ordinarily, such evaluation requires that an aliquot of the process sample be removed from the hot cell, diluted to a calibrated volume in a specified geometrical configuration and measured “off-line” on a gamma ray spectrometer. This is a time consuming process for product isotopes that have relatively short half-lives, like 66 hour 99Mo or 8 day 131I, and introduces the potential for exposure of the analyst to unnecessary radiation.
Accordingly, given the above, a need exists in the art for a system and method for effectively and safely measuring various properties of one or more samples of medical radio-isotopes without exposing testing personnel to undue radiation.